5
Figure 6 –
Wiring Diagram,
Central-Amplified
System with
Page-Muted BGM
Connections
Central-Amplified Talk/Talk Back Systems with
Page Muted BGM
The configuration illustrated in Figure 6 mutes BGM in all
zones when a page is made. The installation requires a pag-
ing amplifier and, in a talk back system, a talk back amplifier.
A background music source is connected directly to the ZPM3
and level adjustments are made using the BGM LEVEL con-
trol on the ZPM3. The background music source must be able
to supply approximately 0 dBm (0.775 VRMS) across a
600-ohm load. Use shielded cable for all talk back amplifier
connections and runs to talk back zones.
Central-Amplified Talk/Talk Back Systems with
BGM to All Unpaged Zones During Pages
A second amplifier is required in the configuration illustrated
in Figure 7, which mutes background music in the paged zone
only (without muting music at any other zones). The BGM
amplifier and paging amplifier should be of equal power.
A talk back amplifier is necessary for two-way operation.
Because of the high gain of the TBA15 talk back channel,
cross talk from the high-voltage bus of the background music
amplifier may be noticeable. To minimize the cross talk, use
the 25V tap on the BGM amplifier and reduce high-frequency
BGM material by lowering the amplifier treble setting. Use
shielded cable for all talk back amplifier connections and runs
to talk back zones. Adjust the paging and BGM volume with
the volume controls on each amplifier (the ZPM3ʼs BGM
LEVEL control is not used in this application).
Central-Amplified Talk/Talk Back Systems
with Dedicated High-Power Zones
When a system requires more than 100 watts of power,
or when one or two zones require more power than the
others, dedicated amplifiers can be installed on the out-
put side of the ZPM3 for these zones. An attenuator pad
(see Figure 8) is required between the input of the am-
plifier(s) and voltage output from the zone(s). Note that
the voltage is reduced approximately 100 times (70V AC
is reduced to 0.7V AC).
Amplified Speaker Systems and BGM to
Unpaged Zones
Systems installed as shown in Figure 9 use a one-way
speaker. Background music is muted in the paged zone
only. The background music sources in this system must
have their own level control since the ZPM3ʼs BGM Level
control is not used.
When there are more than 8 amplified speakers in the sys-
tem, a low-output impedance buffer amplifier is required to
drive the speaker load and reduce volume differences be-
tween single-zone pages and All-Call pages. The Bogen
BUFEX Buffer/Expander/Volume Control should be set high
enough to drive the speakers during an All-Call page but
not so high as to overdrive the speakerʼs input and cause
distortion. When buffering is not necessary, jumpers are
used to connect terminals PIA to POA, and PIB to POB.
Connections to the Paging System
ZPM3
TALKBACK AMP
(OPTIONAL)
+
TEL
LINE
MUTE
GND COM 25V
70V
MUSIC
IN
RING TIP GND COM 25V
70V
BGM / PAGING AMP
OUTPUT
TYP
BGM SOURCE
NOTES:
1. BACKGROUND MUSIC WILL STOP IN ALL ZONES WHENEVER A PAGE IS MADE.
2. FOR CONNECTIONS TO TELEPHONE SYSTEM SEE FIGURES 1, 3, 4, & 5.
